The present invention relates to the field of image processing, and more particularly to processing a video input stream to detect and process slides therein.
Slide-augmented presentations are often video-recorded for later playback or for live remote viewing. In many cases, oral presentations are augmented by slides that are projected onto a surface and captured by a video camera. Typically, an operator positions the video camera to capture both the speaker and the slide projection, occasionally providing a close-up of the slide. In other cases, slides are inserted directly into a video stream using a video mixing system that receives slide images from a computer output. For example, a scan converter may be used to convert the VGA (video graphics adapter) output of a computer into a standardized video signal so that the video mixing system can alternately select between the scan converter and video camera feeds to generate a slide-augmented presentation.
When a video of a slide-augmented presentation is played back to a human viewer, the quality of the video may be inadequate for viewing some or all of the slides, especially if the video is digitized, downsized and compressed for delivery over a low-speed communication channel, such as a computer modem connection. Unfortunately, the options available to the viewer in this circumstance are limited. For example, even if the viewer has access to the source slides used in the video presentation, the source slides and the video presentation are typically uncorrelated. Consequently, if the viewer wishes to view the source slides as they appear in the video presentation, the viewer usually must manually identify the slide from the video, locate the corresponding source slide, and, if the source slide is stored in a computer file, open the source slide using a viewing application in the computer. Moreover, if the source slides are available in alternate languages, the viewer must manually identify the source slide in the language of choice. All these manual activities take time away from the viewer that could otherwise have been spent observing the presentation and the material in the slides, making the video presentation less effective. In presentations that include a relatively rapid sequencing of, slides, the user may be, unable to access the source slides quickly enough to track the presentation at all.
A method and apparatus for automatically generating a slide from a video are disclosed. At least one frame of the video is selected to be a first slide; and a value that indicates a time at which the at least one frame appears in the video is associated with the first slide.